Historically, when and where minorities are given sections in the bookstore, and maintain bookstores of their own, literature written by, for and about them flourishes and crosses over to larger audiences. I'm not engaging in wishful thinking: it's what has really happened.

(a separate issue is that really canny bookstores seeking to cultivate their readership in general, regularly pull books from different categories to make themed displays or even just "staff favorites" displays.)